Canada's diet pill market about to get heavier: Approval sought for new weight-loss drug

With 62 per cent of adult Canadians overweight or obese, the potential market for Belviq is enormous.

Photograph by: Thinkstock
, canada.com

A weight-loss drug recently approved for use in the U.S. may be headed for Canada — a move that could mark a turning point in a controversial corner of medicine that last saw a new drug approved more than a decade ago.

The makers of Belviq say they are poised to market their drug in Canada, a plan that, if approved, would double the country’s prescription diet pill market – from one drug to two.

Doctors who specialize in the treatment of obesity say Belviq, which works on the brain to make people eat less and feel full faster, could breathe new life into a stagnant segment of the medication market.

And with 62 per cent of adult Canadians overweight or obese, the potential market is enormous.

Belviq — whose chemical name is lorcaserin hydrochloride — works on a receptor for serotonin, a brain chemical involved in controlling appetite. In three randomized, controlled trials involving nearly 8,000 obese and overweight patients, nearly half (47 per cent) of those without type 2 diabetes lost at least five per cent of their body weight after one year compared with about 23 per cent of patients treated with placebo. In people with type 2 diabetes, about 38 per cent of the Belviq group lost at least five per cent of their body weight, versus 16 per cent treated with sugar pills.

According to the University of Calgary’s Dr. David Lau, while the weight loss isn’t “huge,” “I think this could be quite exciting.”

“There are some people who really are struggling, and even a little bit of weight loss is extremely important in improving their health status,” said Lau, professor of medicine and chair of the diabetes and endocrine research group at the university.

Belviq was one of two anti-obesity drugs approved back-to-back this summer by the U.S. Food and Drug Administration, the first weight loss drugs to receive the FDA’s blessing in 13 years. The other was Qsymia — a combination of two pills already on the market, phentermine and topiramate.

Phentermine is an amphetamine-derived drug; topiramate is an anti-convulsant. Results from two studies presented to the FDA showed that, one year after treatment, patients on Qsymia had an average weight loss of about seven to nine per cent, depending on the dose. The most common side effects include tingling of hands and feet, dizziness and insomnia.

Neither Belviq nor Qsymia should be used during pregnancy. Babies exposed to topiramate (one of Qsymia’s components) in the first trimester of pregnancy have an increased risk of cleft lips.

Qsymia’s makers haven’t yet submitted their drug for Health Canada approval, according to a spokesperson.

Past attempts to bring — and keep — weight loss drugs on the market have been shaky. Fen-phen was pulled from the market in 1997 after being linked to heart problems. Two years ago, the makers of Meridia voluntarily pulled their drug from drugstore shelves over an increased risk of heart attack and stroke in some people.

That left Canadians with a single option — orlistat, or Xenical, a drug that prevents dietary fats from being absorbed by the intestines but whose side effects include oily or fatty stools.

“There are very high safety standards that are being set up for obesity drugs, because these drugs could potentially be used by many, many people. Even the smallest side effect, if it happens, would happen to a lot of people,” said Dr. Arya Sharma, scientific director of the Canadian Obesity Network. Sharma was on the safety monitoring board for one of the early studies of Belviq.

Belviq can cause side effects such as headache, dizziness, fatigue, dry mouth and nausea.

As with any newly approved drug, the potential long-term risks are unknown, doctors say.

With Meridia and fen-phen, it wasn’t until the drugs started to be prescribed widely that “signals” for severe adverse effects were picked up.

“The hope is that these two new medications won’t suffer the same fate,” said Dr. Sean Wharton, an internal medicine specialist and director of the Wharton Medical Clinic in Burlington, On., one of the largest provincially government-funded weight management clinics in the country.

Another concern is runaway prescribing, Wharton says, where doctors unfamiliar with the medications and their side effects start prescribing them “in a cavalier way” and to all comers, “or people go online to try to get these drugs from other countries.

Tim Kirkham, an authority on the biopsychology of appetite at the University of Liverpool, said people would potentially have to stay on the drugs for life. “It looks like as soon as you stop taking the drugs, your weight will just rebound,” he said.

“The drug company strategies are all based on (brain) signals that are supposed to stop us feeling hungry,” he added. But people can feel full at the end of a meal, “and then start to eat again immediately as soon as something more attractive comes along,” Kirkham said.

Humans are hardwired through evolution to seek out food at every opportunity, he added. In today’s environment, those opportunities are plentiful “and fabulous.”

A more effective strategy would be to develop drugs that target the desire to eat, Kirkham said — “what makes us want to eat,” he said, “or what makes us enjoy eating once we start.”

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